Cataract is an ocular disease whose visual acuity gradually decreases as the crystalline lens that plays the role of a lens becomes cloudy. In general, cataract surgery is performed on a subject's eye with cataract. For example, in cataract surgery, a cloudy lens is removed and an intraocular lens (IOL, hereinafter) is inserted instead. Types of IOLs include those having only the spherical power, toric IOLs capable of correcting astigmatism, and multifocal IOLs that can focus on both far distance and near distance. Prior to cataract surgery, it is necessary to measure eyeball information representing the structure of the subject's eye such as axial length and corneal curvature radius with an ophthalmic apparatus, and determine the power of an IOL from the eyeball information measured.
Such ophthalmic apparatuses are disclosed in, for example, Japanese Patent No. 4523338, Japanese Patent No. 5500587, Japanese Unexamined Patent Application Publication No. 2013-180111 and International Publication WO2013/111090. Japanese Patent No. 452338 discloses an ophthalmic apparatus that includes an optical system for measuring the axial length and an optical system for measuring the refractive power of the subject's eye and is capable of simultaneously performing the measurement of the axial length and the measurement of the refractive power of the subject's eye. Japanese Patent No. 5500587 discloses an ophthalmic apparatus including an optical system for measuring the axial length and an optical system for measuring the shape of the cornea. Japanese Unexamined Patent Application Publication No. 2013-180111 discloses an ophthalmic apparatus capable of measuring the axial length using a technology of swept source optical coherence tomography (OCT, hereinafter). International Publication WO2013/111090 discloses a method of measuring the axial length using a Michelson interferometer.